Resin composition and semiconductor device produced by using the same

ABSTRACT

A resin composition which is excellent in quick curing and can be used for curing in conventionally used ovens, and a semiconductor device which is excellent in reliability such as solder crack resistance or the like when the resin composition is used as a die attach material for semiconductor. Further preferably, a resin composition which has a sufficient low stress property, good adhesion and excellent bleeding property. 
     A resin composition comprising a filler (A), the compound (B) comprising a structure represented by the formula (1) and a functional group represented by the formula (2) and a thermal radical initiator (C), and substantially not containing a photo polymerization initiator.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of Ser. No. 10/593,137, filed Sep. 18,2006, which is a 371 National Phase entry of PCT/JP2005/004700, filedMar. 16, 2005 and claims the benefit of JP 2004-080921, filed Mar. 19,2004, JP 2004-083936, filed Mar. 23, 2004, JP 2004-085885, filed Mar.24, 2004, JP 2004-371083, filed Dec. 22, 2004, and JP 2004-377430, filedDec. 27, 2004, all of which are being incorporated in their entiretyherein by reference.

TECHNICAL FIELD

The present invention relates to a resin composition and a semiconductordevice using the same.

BACKGROUND ART

Aiming at improvement on productivity in a die-bonding process, in theproduction of semiconductors, the in-line curing method in which a diebonder, a wire bonder and the like are arranged on the same line isemployed and it is tending to be more widely used from now on. Hence, incomparison with a curing condition of a die attach paste in theconventionally employed batch method, time required for curing issignificantly limited. For example, with respect to the conventionaloven curing method wherein curing is performed at 150 to 200° C. for 60to 90 minutes, curing is required in a short time such as at 150 to 200°C. for 15 to 90 seconds in the case of the in-line curing method (forexample, see Japanese Patent Application Laid-Open (JP-A) No.2000-63452).

With the enhancement of the processing speed of semiconductor devices, achip surface layer which is weak in mechanical strength is growingpopular. In order to decrease stress against the chip surface, it isrequired to minimize warpage of a semiconductor chip due to thedifference in thermal expansion coefficient between the semiconductorchip and a copper frame. Also, it is required to prevent oxidation ofthe copper frame. Thus, for complying with these requirements, thecuring process in low temperature is desired.

In relation with the above requirements of shortening of curing time andlowering of curing temperature, there is another problem, which is arequirement of thermal management. With significant increase in capacityand processing speed of semiconductor products and moving towards finerdesign rule, a problem of heat which generates during operation ofsemiconductor products is becoming prominent so that releasing the heatfrom semiconductor products, i.e. thermal management, is becoming animportant issue. Hence, measures to mount heat dissipating members suchas heat spreaders, heat sinks or the like on semiconductor products aregenerally employed. However, it is desired for material itself whichbonds heat dissipating members to have higher thermal conductivity.

On the other hand, some forms of semiconductor products may allow asemiconductor chip itself to bond to a heat spreader made of metal, aheat spreader to bond to a die pad portion of a lead frame to which asemiconductor chip is also bonded, or a die pad portion to expose at thepackage surface so as to serve as a heat sink as well. Further, asemiconductor chip may be bonded to an organic substrate having heatdissipating mechanism or the like such as a thermal via or the like.High thermal conductivity is also required to the material which bonds asemiconductor chip in such a case. In this manner, high thermalconductivity is required to die attach materials or materials forbonding heat dissipating members. At the same time, the die attachmaterials and the materials for bonding heat dissipating members arerequired to endure a reflow process performed when a semiconductorproduct is mounted on a substrate, often required to have bonding inlarge area, and also required to have low stress property in order tosuppress warpage or the like due to different thermal expansioncoefficients among component members.

However, a highly thermal conductive adhesive has some problems asfollows (For example, see JP-A No. Hei. 11-43587). Generally, thermallyconductive particles such as metal fillers such as silver powder, copperpowder or the like, or ceramic fillers such as aluminum nitride, boronnitride or the like are added to an organic binder of the highly thermalconductive adhesive at high containing rate. However, since there is alimit in containing amount, there are cases that high thermalconductivity cannot be obtained. Also, though the highly thermalconductive adhesive containing a large amount of solvent has a goodthermal conductivity as a sole cured product, the state when it isapplied to a semiconductor product may not have a stable thermalconductivity since the solvent remains in the cured product or thesolvent volatilizes to leave voids. Even if the adhesive could contain alarge amount of thermally conductive particles, there are cases that lowstress property is insufficient due to high containing rate of thethermally conductive particles.

On the other hand, as a part of considerations for the environment,since it has become to use a lead-free solder as a solder for mountingon a substrate, reflow temperature needs to be raised compared to thereflow temperature when Sn—Pb solder has been used. Because the use ofsuch a lead-free solder causes increase of stress due to raised reflowtemperature, semiconductor products easily generate delamination andthus cracking during the reflow process. Therefore, even higher reflowresistance (high reflow reliability) is demanded to constituentmaterials of semiconductor products than ever.

Further, at present, abolition of lead from semiconductor products is inprogress as a part of considerations for the environment. The case isincreasing to change plating of lead frames to Ni—Pd plating in order toexclude lead from outer lead plating of semiconductor products. In caseof Ni—Pd plating lead frame, there is usually very thin gold plating(gold flash) on the surface to be stable. However, adhesion strength ofa surface decreases in comparison with a normal copper frame with silverplating or the like because of smoothness of Ni—Pd plating and presenceof gold on the surface. Thus, there are cases that a surface of Ni—Pdplated frame is chemically or physically roughened to improve theadhesion strength. However, such a roughened surface often causes resinbleeding of die attach paste which leads to serious problems such asdecline in package reliability.

In relation to the above-mentioned problems, in case of epoxy resin typedie attach paste, which is a major die attach paste at present, curingcan be performed in about 60 seconds by using amine type curing agentsor the like, however, curing in a very short time such as 15 to 30seconds is not handled yet.

On the other hand, it is known, for example, in the following arts thatadhesion particularly with metal improves by using compounds having animide group such as maleimide or the like. That is, Japanese translationof PCT international application (JP-T) No. Hei. 10-505599, JP-T No.2000-514496, JP-T No. 2001-501230, JP-A. No. 11-106455, JP-A No.2001-261939 and JP-A No. 2002-20721. However, there are disadvantagesthat water absorption property of a cured product becomes high when animide compound is used solely so as to deteriorate properties of a curedproduct after moisture absorption since imide compounds have highpolarity. Also, when it is used together with other components, it isnecessary to add components having high polarity in order to mixuniformly. As for these added components, similarly as above, propertiesof a cured product after moisture absorption deteriorate. There has notbeen any satisfactory compound particularly in view of adhesion tohardly adhesive surfaces such as Ni—Pd plated frames or the like, lowstress property against increase of stress caused by raised reflowtemperature due to the change to lead-free solder, and moistureresistance.

Also, a material which has better adhesion to Ni—Pd plated frames thanconventionally used die attach pastes (for example, see JP-A No.2000-273326), has excellent low stress property in terms of low elasticmodulus, and does not generates resin bleeding is desired, however,there has not been satisfactory material.

DISCLOSURE OF INVENTION

The present invention has been achieved in light of the above-statedconventional problems. A first object of the present invention is toprovide a resin composition which is excellent in quick curing and canbe used for curing in conventionally used ovens, and a semiconductordevice which is excellent in reliability such as solder crack resistanceor the like when the resin composition is used as a die attach materialfor semiconductor.

A second object of the present invention is to provide a resincomposition which has a sufficient low stress property, good adhesionand preferably excellent bleeding property, and a semiconductor devicewhich is excellent in reliability when the resin composition is used asa die attach material for semiconductor or a material for bonding a heatdissipating member.

The above objects of the present invention can be attained by a resincomposition comprising a filler (A), the following compound (B) and athermal radical initiator (C), and substantially not containing a photopolymerization initiator, and a semiconductor device of high reliabilitycan be obtained by using the resin composition:

Compound (B):

a compound containing a structure represented by the following formula(1) in a main chain and having at least one functional group representedby the following formula (2):

wherein X¹ is —O—, —COO— or —OCOO—; R¹ is a hydrocarbon group having 1to 6 carbons; “m” is an integer of 1 or more and 50 or less; and if theformula contains two or more parts which are denoted by the same symbol,each of them may be the same or different from each other;

wherein R² is —C₂H₂— or —C₃H₄—; R³ is a hydrocarbon group having 1 to 11carbons; and if the formula contains two or more parts which are denotedby the same symbol, each of them may be the same or different from eachother.

Among the compounds (B), a bismaleimide compound (B′) represented by thefollowing formula (3) is a particularly preferable compound:

wherein X² is —O—, —COO— or —OCOO—; each R⁴ is hydrogen atom or a methylgroup; each R⁵ is a hydrocarbon group having 1 to 11 carbons; each R⁶ isa hydrocarbon group having 3 to 6 carbons; “n” is an integer of 1 ormore and 50 or less; and if the formula contains two or more parts whichare denoted by the same symbol, each of them may be the same ordifferent from each other.

The resin composition of the present invention comprises the filler (A),the compound (B) and the thermal radical initiator (C) as essentialcomponents, and further other optional components can be added. Amongcombinations of such essential components and optional components, thereare first to sixth composition systems as particularly preferablecompositions.

(1) A First Composition System

A first composition system comprises at least the filler (A), thecompound (B), the thermal radical initiator (C) and the followingcompound (D), substantially not containing a photo polymerizationinitiator:

Compound (D):

A compound (D) is a compound containing a structure represented by theformula (4) in a main chain and having at least one functional grouphaving a polymerizable C—C unsaturated bond:

wherein X³ is —O—, —COO— or —OCOO—; R⁷ is a hydrocarbon group having 3to 6 carbons; “p” is an integer of 1 or more and 50 or less; and if theformula contains two or more parts which are denoted by the same symbol,each of them may be the same or different from each other.(2) A Second Composition System

A second composition system comprises at least the filler (A), thecompound (B), the thermal radical initiator (C), the compound (D) usedin the first composition system and a combination of the followingcompound (L) and the following compound (M), substantially notcontaining a photo polymerization initiator:

Compound (L):

A compound (L) is a compound containing the following structurerepresented by the formula (11) in a main chain and having at least oneglycidyl group:

wherein X⁷ is —O—, —COO— or —OCOO—; R¹⁵ is a hydrocarbon group having 3to 6 carbons; “u” is an integer of 2 or more and 50 or less; and if theformula contains two or more parts which are denoted by the same symbol,each of them may be the same or different from each other;Compound (M):

A compound (M) is a compound having a functional group which can reactwith the glycidyl group of the compound (L).

(3) A Third Composition System

A third composition system comprises at least the filler (A), thecompound (B), the thermal radical initiator (C) and the followingacrylic ester compound (E), substantially not containing a photopolymerization initiator:

Acrylic Ester Compound (E):

An acrylic ester compound (E) is a compound represented by the followingformula (5):

wherein R⁸ is hydrogen atom or a methyl group; R⁹ is a hydrocarbon grouphaving 1 to 3 carbons; “x”, “y” and “z” are in the relationshipexpressed by (x+y+z)=3, 1≦x≦3, 0≦y≦2 and 0≦z≦2; and if the formulacontains two or more parts which are denoted by the same symbol, each ofthem may be the same or different from each other.(4) A Forth Composition System

A forth composition system comprises at least the filler (A), thecompound (B), the thermal radical initiator (C) and the followingacrylamide compound (F), substantially not containing a photopolymerization initiator:

Acrylamide Compound (F):

An acrylamide compound (F) is a compound containing a structurerepresented by the following formula (6) in a main chain and having atleast one functional group represented by the following formula (7):

Formula (7):CH₂═CR¹¹—CONH—  (7)wherein X⁴ is —O—, —COO— or —OCOO—; R¹⁰ is a hydrocarbon group having 3to 6 carbons; R¹¹ is hydrogen atom or a methyl group; “r” is an integerof 1 or more and 50 or less; and if the formula contains two or moreparts which are denoted by the same symbol, each of them may be the sameor different from each other.(5) A Fifth Composition System

A fifth composition system comprises at least the filler (A), thecompound (B), the thermal radical initiator (C) and the following allylester compound (G), substantially not containing a photo polymerizationinitiator:

Allyl Ester Compound (G):

An allyl ester compound (G) is a compound having at least one functionalgroup represented by the following formula (8):Formula (8):CH₂═CH—CH₂—OCO—R¹²—  (8)wherein R¹² is a hydrocarbon group having 2 to 8 carbons.(6) A Sixth Composition System

A sixth composition system comprises at least the filler (A), thecompound (B), the thermal radical initiator (C), the following compound(H) and a reactive diluent (I), substantially not containing a photopolymerization initiator:

Compound (H):

A compound (H) is a compound derived from a hydrocarbon having at leastone C—C unsaturated bond in one molecule, which has a number averagemolecular weight of 500 to 5,000, contains a structures represented bythe following formula (10) at its modified position, and has at leastone functional group having a polymerizable C—C unsaturated bond:

wherein X⁶ is —O—, —COO— or —OCOO—; R¹⁴ is a hydrocarbon group having 3to 6 carbons; “t” is an integer of 1 or more and 50 or less; and if theformula contains two or more parts which are denoted by the same symbol,each of them may be the same or different from each other.

A resin composition of the present invention, particularly a resincomposition which belongs to any of the above-mentioned first to sixthcomposition systems, is excellent in adhesion strength, quickcurability, moisture resistance and low stress property, is alsoapplicable to the oven curing, and is excellent in adhesion particularlybetween a copper lead frame and a semiconductor chip when it is used asan adhesive of a semiconductor chip. Also, the obtained semiconductordevice is excellent in solder crack resistance. As a result, asemiconductor device which is high in reliability can be obtained.

Also, among the resin compositions of the present invention, thecomposition which belongs to the third composition system exhibitsexcellent bleeding property as well as good low stress property and goodadhesion, therefore, a semiconductor device excellent in reliability canbe obtained by using the resin composition as a die attach material fora semiconductor or a bonding material for a heat dissipating member oran attach material for a heat sink member.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the embodiment of the present invention will be explainedin more detail. In the present invention, “(meth)acryl” denotes acryland/or methacryl, and “(meth)acryloyl” denotes acryloyl and/ormethacryloyl.

According to the present invention, a resin composition significantlysuitable for as an adhesive for a semiconductor chip or a heatdissipating member can be provided, wherein the resin compositioncomprises at least a filler (A), the following compound (B) and athermal radical initiator (C), substantially not containing a photopolymerization initiator:

Compound (B):

a compound containing a structure represented by the following formula(1) in a main chain and having at least one functional group representedby the following formula (2):

wherein X¹ is —O—, —COO— or —OCOO—; R¹ is a hydrocarbon group having 1to 6 carbons; “m” is an integer of 1 or more and 50 or less; and if theformula contains two or more parts which are denoted by the same symbol,each of them may be the same or different from each other;

wherein R² is —C₂H₂— or —C₃H₄—; R³ is a hydrocarbon group having 1 to 11carbons; and if the formula contains two or more parts which are denotedby the same symbol, each of them may be the same or different from eachother.

As the filler (A) used in the present invention, silver powder is oftenused. A containing amount thereof is normally 70 to 95 wt % in a resincomposition. As the filler (A) besides the above, for example, goldpowder, copper powder, nickel powder, palladium powder, aluminumnitride, boron nitride, calcium carbonate, silica, alumina or the likecan also be used.

When using the silver powder, generally, commercially available silverpowder (A) for electronic material may be used. As such silver powder,reduced powder, atomized powder and the like are available. Preferableparticle size is 1 to 30 μm in average particle size since if theaverage particle size is smaller than this range, viscosity of a resincomposition becomes too high, and if the average particle size is largerthan this range, it will cause clogging of dispensing nozzle. Silverpowder other than one for electronic material may include large amountof ionic impurity, thus, materials should be carefully selected. Silverpowder having silver containing rate of 90 wt % or more may be usedpreferably. Silver powder having silver containing rate of 90 wt % ormore may be used as alloy of the silver powder and other metals,however, silver powder having silver containing rate lower than theabove is not preferable as thermal conductivity may decrease. The formmay not be particularly limited and may be in a flake-like form,spherical form or the like. Preferably, silver powder in a flake-likeform may be used and generally contained at 70 to 95 wt % in a resincomposition. If the containing rate of silver powder is lower than theabove, thermal conductivity, and in some cases, required electricconductivity may be deteriorated. If the containing rate of silverpowder is higher than the above, viscosity of a resin composition maybecome too high.

In the compound (B) containing a structure represented by the formula(1) in a main chain and having at least one functional group representedby the formula (2) used in the present invention, it is preferable thathydrocarbon R¹ contained in a repeating unit of the main chain does notcontain an aromatic group. Also, hydrocarbon R¹ may have 1 to 6 carbons,however, it is preferable to limit in the range of 3 to 6. By allowinghydrocarbon R¹ to have 3 or more carbons, deterioration of moistureresistivity of a cured product can be prevented, and it is possible tomake properties such as adhesion strength or the like be hard todeteriorate under severe condition in water treatment such as PCT (thepressure cooker test) or the like. Hydrocarbon R¹ is set to have 6 orless carbons since if there are more carbons, hydrophobic property of aresin becomes too strong and adhesion strength to a metal surface or thelike which is easily oxidized such as copper or the like maydeteriorate. A hydrocarbon group having 3 or 4 carbons is morepreferable.

In the repeating unit, —O—, —COO— or —OCOO— is contained as a partrepresented by a symbol “X¹”. They are necessary to exhibit flexibilityof a cured product and also to be in liquid state as raw material or toimprove solubility to other components. The part represented by thesymbol “X¹” is preferably —O— (ether bond).

Further, a repeating number “m” may be in the range of 1 to 50. However,if the repeating number “m” is 1, flexibility of a targeted curedproduct may not be exhibited, thus, the repeating number may bepreferably 2 or more. If the repeating number “m” becomes more than 50,viscosity becomes too high and it is not preferable for practical use.If a repeating unit satisfies the above condition, two or more kinds ofsuch repeating units may be used or a copolymer with other component maybe used.

Further, the functional group represented by the formula (2) isnecessary to exhibit good adhesion strength to a metal plated surfacesuch as silver plating or nickel/palladium plating, and two functionalgroups may be preferably contained in one molecule.

Hydrocarbon R² contained in the functional group may preferably be—C₂H₂—. Hydrocarbon R³ contained in the functional group preferably doesnot contain an aromatic group and may have 1 to 5 carbons, and —CH₂— isparticularly preferable as R³.

Among the compounds (B), a bismaleimide compound (B′) represented by thefollowing formula (3) is particularly preferable.

wherein X² is —O—, —COO— or —OCOO—; each R⁴ is hydrogen atom or a methylgroup; each R⁵ is a hydrocarbon group having 1 to 11 carbons; each R⁶ isa hydrocarbon group having 3 to 6 carbons; “n” is an integer of 1 ormore and 50 or less; and if the formula contains two or more parts whichare denoted by the same symbol, each of them may be the same ordifferent from each other.

The bismaleimide compound (B′) exhibits good fluidity and good adhesioneven if a filler (A), particularly silver powder, is compounded. Amaleimide group or a derivative thereof is contained in the bismaleimidecompound (B′) as a functional group. By using them together with athermal radical initiator (C) to be hereinafter described, goodreactivity is exhibited when heated, and due to polarity of an imidegroup, good adhesion to hardly adhesive metal surfaces, for example,silver plating, Ni—Pd plating or the like, can be exhibited.

The bismaleimide compound (B′) has two functional groups in one moleculesince the following are taken into account. If there is one functionalgroup, improvement of adhesion strength is not sufficient than expected.If there are three or more functional groups, molecular weight increasesso as to raise viscosity which leads a resin composition to have highviscosity.

Conventionally, as a difunctional maleimide compound, maleimidecompounds using aromatic amine as raw material are well known, however,it is difficult to obtain the aromatic amine base bismaleimde in liquidform in room temperature as the aromatic amine base bismaleimde hasgenerally high crystalline property. Such maleimide compound is solublein solvents having high boiling point and polarity such asdimethylformamide, N-methylpyrrolidone or the like, however, when suchsolvents are used, voids are generated upon heat-curing a resincomposition to deteriorate thermal conductivity, thus, such solventscannot be used. As the bismaleimide compound (B′) is in liquid form atroom temperature, it is not necessary to use a solvent. Even if it isnecessary to dilute, the bismaleimide compound (B′) exhibits goodaffinity with generally used vinyl compounds in liquid form, thus, itcan be diluted by vinyl compounds in liquid form. Among them, a vinylcompound having a (meth)acryloyl group is suitably used as a diluentsince it can be copolymerized with the bismaleimide compound (B′).

In the bismaleimide compound (B′), R⁵ of the formula (3) may be ahydrocarbon group having 1 to 11 carbons, preferably not containing anaromatic. Also, it is preferable that the hydrocarbon group has 1 to 5carbons. If there are 6 or more carbons, crystalline property becomeshigh and may be unable to be used. R⁵ preferably may have only onecarbon or 5 carbons, and particularly R⁵ having 1 carbon is preferable.

R⁶ of the formula (3) is a hydrocarbon group having 3 to 6 carbons,preferably not containing an aromatic group. If there is less carbon,deterioration of moisture resistivity may occur and it causesdeterioration of properties such as adhesion strength or the like undersevere condition in water treatment such as PCT or the like. On theother hand, if there are more carbons, hydrophobic property of a resincomposition becomes too strong and adhesion strength to a metal surfaceor the like which is easily oxidized such as copper or the like maydeteriorate and also crystalline property becomes too high. Thus, eithercase cannot be used. A hydrocarbon group having 3 or 4 carbons is morepreferable.

—O—, —COO— or —OCOO— is contained as X² of the formula (3). They arenecessary to exhibit flexibility of a cured product and also to be inliquid state as raw material or to improve solubility to othercomponents. Among them, preferably X² may be —O—.

Further, the repeating number “n” of the repeating unit contained in theformula (3) may be 50 or less. If the repeating number “n” becomes over50, viscosity becomes too high and it is not preferable for practicaluse. If a repeating unit satisfies the above condition, two or morekinds of such repeating units may be used or a copolymer with othercomponent may be used.

Such a composition is available by reacting a compound having an aminogroup and a carboxyl group, wherein the compound has a hydrocarbon grouphaving 1 to 5 carbons between the amino group and the carboxyl group(namely, amino acid such as glycine, alanine, aminocaproic acid or thelike), and maleic anhydride or the derivative thereof to synthesize amaleimide of amino acid, and reacting the product with polyalkyleneoxide diol, polyalkylene ester diol or the like.

In the present invention, a thermal radical initiator (C) is used as areaction initiator for the above-mentioned compound (B) and otherpolymerizable components to be mentioned below. Generally, there is noparticular limit if it can be used as a thermal radical initiator.Preferable thermal radical initiator has a decomposition temperature of40 to 140° C. in terms of a decomposition starting temperature measuredby a rapid heating test wherein decomposition starting temperature isdetected so as that 1 g of sample on an electric heating plate is heatedwhile rising temperature by 4° C./min. If the decomposition temperatureis less than 40° C., storage stability of a resin composition at normaltemperature deteriorates, and if the decomposition temperature is over140° C., curing time becomes extremely long which is not preferable.

As examples of a thermal radical polymerization initiator satisfyingsuch requirement, there may be methyl ethyl ketone peroxide,methylcyclohexanone peroxide, methylacetoacetate peroxide, acetylacetoneperoxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane,1,1-bis(t-hexylperoxy)cyclohexane,1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane,1,1-bis(t-butylperoxy)cyclohexane,2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane,1,1-bis(t-butylperoxy)cyclododecane,n-butyl-4,4-bis(t-butylperoxy)valerate, 2,2-bis(t-butylperoxy)butane,1,1-bis(t-butylperoxy)-2-methylcyclohexane, t-butylhydro peroxide,p-methanehydro peroxide, 1,1,3,3-tetramethylbutylhydro peroxide,t-hexylhydro peroxide, dicumyl peroxide,2,5-dimethyl-2,5-bis(t-butylperoxy)hexane,α,α′-bis(t-butylperoxy)diisopropylbenzene, t-butylcumyl peroxide,di-t-butyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3,isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoylperoxide, lauroyl peroxide, cinnamic acid peroxide, m-toluoyl peroxide,benzoyl peroxide, diisopropyl peroxydicarbonate,bis(4-t-butylcyclohexyl)peroxydicarbonate,di-3-methoxybutylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate,di-sec-butylperoxydicarbonate, di(3-methyl-3-methoxybutyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxy dicarbonate,α,α′-bis(neodecanoylperoxy)diisopropylbenzene, cumylperoxyneodecanoate,1,1,3,3-tetramethylbutylperoxy neodecanoate,1-cyclohexyl-1-methylethylperoxy neodecanoate, t-hexylperoxyneodecanoate, t-butylperoxy neodecanoate, t-hexylperoxy pivalate,t-butylperoxy pivalate,2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane,1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate,1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate,t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate,t-butylperoxy isobutyrate, t-butylperoxy maleic acid, t-butylperoxylaurate, t-butylperoxy-3,5,5-trimethyl hexanoate, t-butylperoxyisopropylmonocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate,2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, t-butylperoxy acetate,t-hexylperoxy benzoate, t-butylperoxy-m-toluoyl benzoate, t-butylperoxybenzoate, bis(t-butylperoxy)isophthalate, t-butylperoxyallylmonocarbonate, 3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone or thelike.

They may be used solely or in mixture of two or more kinds to controlcurability.

Although it is not particularly limited, it is preferable that thethermal radical initiator (C) is contained by 0.001 to 2 wt % in a resincomposition.

A resin composition of the present invention is generally used underlighting such as a fluorescent light or the like, hence, if a photopolymerization initiator is contained, rise in viscosity is observed dueto the reaction while using the resin composition. Thus substantially, aphoto polymerization initiator cannot be contained. The term“substantially” means that a very small amount of a photo polymerizationinitiator may be present as far as rise in viscosity is not observed,and preferably a photo polymerization initiator is not contained.

A resin composition of the present invention comprises a filler (A), thecompound (B) and a thermal radical initiator (C), and together at leastone selected from the following compound (D), the following acrylicester compound (E), the following acrylamide compound (F), the followingallyl ester compound (G) and the following compound (H), thereby, betteradhesion property and physical property after curing, for example, oneor more properties among quick curing, adhesion, reflow resistance, lowstress property, bleeding property and other properties can be improved.

Similarly to the compound (B), these compounds (D) to (H) are componentswhich can start radical polymerization reaction by a thermal radicalinitiator and copolymerizable with the compound (B).

A compound (D) used in the present invention is a compound containing astructure represented by the formula (4) in a main chain and having atleast one functional group having a polymerizable C—C unsaturated bond:

wherein X³ is —O—, —COO— or —OCOO—; R⁷ is a hydrocarbon group having 3to 6 carbons; “p” is an integer of 1 or more and 50 or less; and if theformula contains two or more parts which are denoted by the same symbol,each of them may be the same or different from each other.

The compound (D) limits the hydrocarbon group R⁷ contained in arepeating unit (X³—R⁷) in a main chain to a hydrocarbon group having 3to 6 carbons since if there is less carbon, deterioration of moistureresistivity may occur and it causes deterioration of properties such asadhesion strength or the like under severe condition in water treatmentsuch as PCT or the like. On the other hand, if there are more carbons,hydrophobic property of a resin becomes too strong and adhesion strengthto a metal surface or the like which is easily oxidized such as copperor the like may deteriorate.

In the repeating unit (X³—R⁷), —O—, —COO— or —OCOO— is contained as apart represented by a symbol “X³”. They are necessary to allow a curedproduct to exhibit flexibility and sufficient adhesion strength.

It is not preferable for practical use that the repeating number “p”becomes over 50 as viscosity rises. If the repeating unit satisfies theabove condition, two or more kinds of such repeating units may be usedor a copolymer with other component may be used.

As a functional group having a polymerizable C—C unsaturated bond, theremay be a (meth)acryloyl group, a vinyl group or the like, but may not beparticularly limited thereto and plural kinds may be used together. Thecompound (D) preferably has two or more C—C unsaturated bonds in onemolecule.

The acrylic ester compound (E) is a compound represented by thefollowing formula (5):

wherein R⁸ is hydrogen atom or a methyl group; R⁹ is a hydrocarbon grouphaving 1 to 3 carbons and preferably an alkyl group; “x”, “y” and “z”are in the relationship expressed by (x+y+z)=3, 1≦x≦3, 0≦y≦2 and 0≦z≦2;and if the formula contains two or more parts which are denoted by thesame symbol, each of them may be the same or different from each other.

Generally, a low viscosity acrylic ester compound such asmono(meth)acrylate, di(meth)acrylate or the like is used as a reactivediluent. By using the acrylic ester compound (E) represented by theformula (5), good adhesion and excellent bleeding property can beexhibited.

The term “bleeding” means a phenomenon wherein a resin component of aresin composition spreads on a surface to be bonded when the resincomposition is applied on the parts to be bonded such as a lead frame orthe like or during heat-curing. It is an undesirable phenomenon as thebleeding may cause inferiority of the ground bonding (wire bonding froma semiconductor chip to a die pad), or may cause decline in adhesionstrength of encapsulant of a die pad and thus delamination, andcracking. Herein, the term “excellent in bleeding property” means thatbreeding is hard to generate, that is, the above-mentioned problems arehard to occur. As a particularly preferable compound (E) represented bythe formula (5), there may be a compound wherein R⁸ is a methyl group,R⁹ is a methyl group, x=1, y=1, and z=1 or a compound wherein R⁸ is amethyl group, x=2, y=1, and z=0.

The acrylamide compound (F) used in the present invention is a compoundcontaining a structure represented by the following formula (6) in amain chain and having at least one functional group represented by thefollowing formula (7):

Formula (7):CH₂═CR¹¹—CONH—  (7)wherein X⁴ is —O—, —COO— or —OCOO—; R¹⁰ is a hydrocarbon group having 3to 6 carbons; R¹¹ is hydrogen atom or a methyl group; “r” is an integerof 1 or more and 50 or less; and if the formula contains two or moreparts which are denoted by the same symbol, each of them may be the sameor different from each other.

The acrylamide compound (F) limits the hydrocarbon group R¹⁰ containedin a repeating unit (X⁴—R¹⁰) in a main chain to a hydrocarbon grouphaving 3 to 6 carbons, preferably 3 or 4 carbons, since If there is lesscarbon, deterioration of moisture resistivity may occur and it causesdeterioration of properties such as adhesion strength or the like undersevere condition in water treatment such as PCT or the like. On theother hand, if there are more carbons, hydrophobic property of a resinbecomes too strong and adhesion strength to a metal surface or the likewhich is easily oxidized such as copper or the like may deteriorate.

In the repeating unit (X⁹—R¹⁰), any bond of —O—, —COO— or —OCOO—,preferably —O—, may be contained as a part represented by a symbol “X⁴”.They are necessary to exhibit flexibility of a cured product and also tobe in liquid state as raw material or to improve solubility to othercomponents.

It is not preferable for practical use that the repeating number “r”becomes over 50 as viscosity rises. If the repeating unit satisfies theabove condition, two or more kinds of such repeating units may be usedor a copolymer with other component may be used.

Further, the functional group represented by the formula (7) isnecessary to exhibit good adhesion strength to a metal plated surfacesuch as silver plating or nickel/palladium plating, and two functionalgroups may be preferably contained in one molecule.

As the acrylamide compound (F), there may be a compound which isobtained by reacting a compound having a hydroxyl group on each end, atleast one repeating unit selected from propylene oxide tetramethyleneoxide and butylene oxide and a molecular weight of 300 to 2500 withdibasic acid anhydride such as succinic anhydride followed by reactingwith (meth)acrylamide having a hydroxyl group such as2-hydroxyethyl(meth)acrylamide or the like.

The allyl ester compound (G) used in the present invention is a compoundhaving at least one functional group represented by the followingformula (8):Formula (8):CH₂═CH—CH₂—OCO—R¹²—  (8)wherein R¹² is a hydrocarbon group having 2 to 8 carbons.

The allyl ester compound (G) having a functional group represented bythe formula (8) can be copolymerized with the compound (B) having afunctional group represented by the formula (2), and has excellentbalance between adhesion and low stress property of a cured product.

As for number of functional groups represented by the formula (8), atleast one functional group is necessary in one molecule from theviewpoint of curability. More preferably, two or more functional groupsmay be contained in one molecule. R¹² contained in the functional groupis a hydrocarbon group having 2 to 8 carbons and may be aliphatic chain,alicyclic or aromatic group. It is preferable that an aromatic group maynot be contained from the viewpoint of adhesion.

Particularly, when low stress property is required to a cured product, astructure represented by the following formula (9) is preferablycontained in a molecule structure.Formula (9):—(X⁵—R¹³)_(s)—  (9)wherein X⁵ is —O—, —COO— or —OCOO—; R¹³ is a hydrocarbon group having 3to 6 carbons; “s” is an integer of 1 or more and 50 or less; and if theformula contains two or more parts which are denoted by the same symbol,each of them may be the same or different from each other.

R¹³ contained in the structure represented by the formula (9) is ahydrocarbon group having 3 to 6 carbons. It is not preferable if thereis less carbon as it is more likely to absorb water and also if thereare more carbons as hydrophobic property becomes too strong todeteriorate adhesion strength.

The repeating number “s” is an integer of 1 or more and 50 or less. Ifthe number is more than 50, molecule weight becomes too large to causeincrease in viscosity and not preferable from the viewpoint ofworkability. More preferable hydrocarbon group may have 3 to 4 carbonsand a repeating number may be 2 to 20.

The compound (H) used in the present invention is a derivative of ahydrocarbon having at least one C—C unsaturated bond in one molecule,which has a number average molecular weight of 500 to 5,000, contains astructure represented by the following formula (10) at its modifiedposition, and has at least one functional group having a polymerizableC—C unsaturated bond:

wherein X⁶ is —O—, —COO— or —OCOO—; R¹⁴ is a hydrocarbon group having 3to 6 carbons; “t” is an integer of 1 or more and 50 or less; and if theformula contains two or more parts which are denoted by the same symbol,each of them may be the same or different from each other.

In the compound (H), it is preferable that X⁶ in the structurerepresented by the formula (10) is —O—.

Also, it is preferable that a hydrocarbon having at least one C—Cunsaturated bond in one molecule to be led or converted to the compound(H) is a butadiene polymer.

It is preferable that a hydrocarbon having at least one C—C unsaturatedbond in one molecule to be led to the compound (H) is an isoprenepolymer.

It is preferable that the polymerizable C—C unsaturated bond of thecompound (H) is a (meth)acryl group.

The compound (H) is a reacted product of a homopolymer of diene compoundsuch as polyisoprene, polybutadiene or the like having a hydroxyl group,a carboxyl group, a glycidyl group or the like or a copolymer of a dienecompound and styrene or the like (a first component) and a compoundhaving a functional group reactive to the hydroxyl group, the carboxylgroup, the glycidyl group or the like of the polymer, a functional grouphaving a polymerizable C—C unsaturated bond, and a repeating unitsimilar to the repeating unit (X¹—R¹) in the compound (B) (a secondcomponent). Herein, as a functional group having polymerizable C—Cunsaturated bond contained in the second component, there may be a(meth)acryloyl group, a vinyl group, or a functional group representedby the formula (2). If a number average molecular weight of the compound(H) is less than 500, expected flexibility may not be exhibited, thus itis not preferable, and if the number average molecular weight is morethan 5,000, viscosity becomes too high and it is not preferable forpractical use.

A homopolymer of diene compound such as polyisoprene, polybutadiene orthe like or a copolymer of a diene compound and styrene or the like arenecessary to allow a cured product to exhibit flexibility, however, ifthese compound are used without modification, compatibility with thecompound (B), a diluent or the like is not good so as to cause phaseseparation during curing. Therefore, in the present invention,modification is performed by reacting a homopolymer of diene compoundsuch as polyisoprene, polybutadiene or the like having a hydroxyl group,a carboxyl group, a glycidyl group or the like or a copolymer of a dienecompound and styrene or the like (a first component) with a compoundhaving a functional group reactive to the hydroxyl group, the carboxylgroup, the glycidyl group or the like of the polymer, a functional grouphaving a polymerizable C—C unsaturated bond, and a repeating unitsimilar to the repeating unit used for the compound (B) (a secondcomponent) to improve uniformity of the whole system and to be taken ina cured product by the reaction, therefore, the present invention canprovide cured products having similar morphology even reaction isperformed quickly or for a long time in a oven or the like.

Specifically, for example, the following modified product may be used,which may be used solely or in combination:

(1) A compound obtained by reacting polybutadiene having a hydroxylgroup with cyclohexane tetracarboxylic dianhydride of equimolar amountas the hydroxyl group, and thereafter, half esterifying it withpolytetramethyleneglycol methacrylate having a hydroxyl group at the endposition;

(2) A compound obtained by reacting a maleated polybutadiene withhexamethylene diamine of equimolar amount as residue of maleic acid, andthereafter, reacting it with maleic anhydride followed bycyclodehydration;

(3) A compound obtained by half esterifying maleated polybutadiene withpolytetramethyleneglycol methacrylate having a hydroxyl group ofequimolar amount as residue of maleic acid; and

(4) A compound obtained by esterifying polybutadiene having a carboxylgroup at the end position with polytetramethyleneglycol methacrylate.

In the present invention, a reactive diluent (I) may be added to a resincomposition. As a diluent of the compound (B), a vinyl compound which isin liquid form can be used. It is preferable that the vinyl compound inliquid form is a compound having a (meth)acryloyl group from theviewpoint of copolymerization capability with the functional grouprepresented by the formula (2) of the compound (B).

Such a compound, for example, single or plural kinds amongalicyclic(meth)acrylic ester, aliphatic(meth)acrylic ester,aromatic(meth)acrylic ester, aliphatic dicarboxylic acid (meth)acrylicester, aromatic dicarboxylic acid (meth)acrylic ester or the like can beused and may preferably have the same or less compounding amount as thecompounds (E). if a resin composition contains the compounds (E).

As such a general reactive diluent, there may be methyl(meth)acrylate,ethyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate,tert-butyl(meth)acrylate, isodecyl(meth)acrylate, lauryl(meth)acrylate,tridecyl(meth)acrylate, cetyl(meth)acrylate, stearyl(meth)acrylate,isoamyl(meth)acrylate, isostearyl(meth)acrylate, behenyl(meth)acrylate,2-ethylhexyl(meth)acrylate, alkyl(meth)acrylate other than above,cyclohexyl(meth)acrylate, tert-butylcyclohexyl(meth)acrylate,tetrahydrofurfuryl(meth)acrylate, benzyl(meth)acrylate,phenoxyethyl(meth)acrylate, isobornyl(meth)acrylate,glycidyl(meth)acrylate, trimethylol propanetri(meth)acrylate, zincmono(meth)acrylate, zinc di(meth)acrylate,dimethylaminoethyl(meth)acrylate, diethylaminoethyl(meth)acrylate,neopentylglycol(meth)acrylate, trifluoromethyl(meth)acrylate,2,2,3,3-tetrafluoropropyl(meth)acrylate,2,2,3,3,4,4-hexafluorobutyl(meth)acrylate, perfluorooctyl(meth)acrylate,perfluorooctylethyl(meth)acrylate, ethyleneglycol di(meth)acrylate,propyleneglycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate,1,6-hexanediol di(meth)acrylate, 1,9-nonandiol di(meth)acrylate,1,3-butanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate,tetramethyleneglycol mono(meth)acrylate, tetramethyleneglycoldi(meth)acrylate, methoxyethyl(meth)acrylate, butoxyethyl(meth)acrylate,ethoxydiethyleneglycol(meth)acrylate, methoxypolyalkyleneglycolmono(meth)acrylate, octoxypolyalkyleneglycol mono(meth)acrylate,lauroxypolyalkyleneglycol mono(meth)acrylate, stearoxypolyalkyleneglycolmono(meth)acrylate, allyloxypolyalkyleneglycol mono(meth)acrylate,nonylphenoxypolyalkyleneglycol mono(meth)acrylate, N,N′-methylenebis(meth)acrylic amide, N,N′-ethylene bis(meth)acrylic amide,1,2-di(meth)acrylic amide ethyleneglycol,di(meth)acryloyloxymethyltricyclodecane, 2-(meth)acryloyloxyethylsuccinate, 2-(meth)acryloyloxyethyl hexahydrophthalate,2-(meth)acryloyloxyethyl, N-(meth)acryloyloxyethylmaleimide,N-(meth)acryloyloxyethylhexahydrophthal imide,N-(meth)acryloyloxyethylphthal imide or the like.

In the present invention, a silane coupling agent (J) can be used forthe purpose of obtaining good adhesion. Particularly, a silane couplingagent having a S—S bond is preferably used together with silver powder(A) since not only adhesion strength to the parts to be bonded improvesbut also cohesion of a cured product of resin composition improves asthe silane coupling agent also reacts with the silver powder, therefore,particularly excellent adhesion can be obtained.

As such a silane coupling agent having a S—S bond, there may bebis(trimethoxysilylpropyl)tetrasulfide,bis(triethoxysilylpropyl)tetrasulfide,bis(tributoxysilylpropyl)tetrasulfide,bis(dimethoxymethylsilylpropyl)tetrasulfide,bis(diethoxymethylsilylpropyl)tetrasulfide,bis(dibutoxymethylsilylpropyl)tetrasulfide,bis(trimethoxysilylpropyl)disulfide, bis(triethoxysilylpropyl)disulfide,bis(tributoxysilylpropyl)disulfide,bis(dimethoxymethylsilylpropyl)disulfide,bis(diethoxymethylsilylpropyl)disulfide,bis(dibutoxymethylsilylpropyl)disulfide, or the like.

Also, it is more preferable to use a silane coupling agent having aglycidyl group together with the silane coupling agent having an S—Sbond. As the silane coupling agent having a glycidyl group, there may be2-(3,4-epoxycyclohexyl)ethyltrimethoxy silane,3-glycycloxypropyltrimethoxy silane, 3-glycycloxypropylmethyldiethoxysilane, 3-glycycloxypropyltriethoxy silane or the like.

In the present invention, it is also possible to add a compound (K)having a glycidyl group other than the above-mentioned coupling agenthaving a glycidyl group. Particularly, if good adhesion with a coppersurface is required, the addition of the compound having a glycidylgroup is effective. As the compound having a glycidyl group, there maybe used one obtained by glycidyl etherifying bisphenol A, bisphenol F orother bisphenols, one obtained by glycidyl etherifying phenolnovolac,cresolnovolac or other phenols and an epoxy compound of aminophenol. Forthe purpose of decreasing viscosity, there may be aliphatic glycidylethers, glycidyl ethers in a form of an aliphatic ring produced byhydrogenation, alicyclic epoxy compound or the like, if required,imidazole or other compounds which react with a glycidyl group may beadded. Particularly, in order to balance storage stability andreactivity, it is preferable to use an adduct of 2-methylimidazole and2,4-diamino-6-vinyltriazine or2-phenyl-4-methyl-5-hydroxymethylimidazole.

In the present invention, a combination of the following compound (L)and the following compound (M) may be further added to a resincomposition:

Compound (L):

A compound (L) is a compound containing the following structurerepresented by the formula (11) in a main chain and having at least oneglycidyl group:

wherein X⁷ is —O—, —COO— or —OCOO—; R¹⁵ is a hydrocarbon group having 3to 6 carbons; “u” is an integer of 2 or more and 50 or less; and if theformula contains two or more parts which are denoted by the same symbol,each of them may be the same or different from each other;Compound (M):

A compound (M) is a compound having a functional group which can reactwith the glycidyl group of the compound (L).

The compound (L) having a glycidyl group limits the hydrocarbon groupR¹⁵ contained in a repeating unit in a main chain to a hydrocarbon grouphaving 3 to 6 carbons since if R¹⁵ has less carbon, deterioration ofmoisture resistivity of a cured product may occur and it causesdeterioration of properties such as adhesion strength or the like undersevere condition in water treatment such as PCT or the like. On theother hand, if R¹⁵ has more carbons, hydrophobic property of a resinbecomes too strong and adhesion strength to a metal surface or the likewhich is easily oxidized such as copper or the like may deteriorate.

The repeating unit contains —O—, —COO— or —OCOO— as a part representedby the symbol “X⁷” since it is necessary to exhibit flexibility of acured product and sufficient adhesion strength.

Also, the glycidyl group is necessary since introduction of a glycidylgroup is effective in view of bonding to copper particularly. Byintroducing a glycidyl group, compatibility to various surfaces to bebonded can be improved.

Further, it is preferable that the repeating unit is the same as orsimilar to the repeating unit (X¹—R¹) of the compound (B) in order toimprove uniformity of a resin composition, particularly uniformity aftercuring. If the repeating unit is not similar, separation proceedsparticularly when curing is performed by an oven or the like for a longtime so that properties of a cured product may not be sufficientlyexhibited.

It is not preferable for practical use that the repeating number “u”becomes over 50 as viscosity rises. If the repeating unit satisfies theabove condition, two or more kinds of such repeating units may be usedor a copolymer with other component may be used.

As the compound (M) having a functional group reactive with the glycidylgroup of the compound (L), a generally used curing agent of an epoxyresin may be used. For example, there may be phenol compounds, aminecompounds, imidazole compounds or the like, but may not be limited.

In a resin composition of the present invention, additives such as adefoaming agent, a surfactant, various polymerization inhibitors, anoxidation inhibitor or the like may be used, if required.

A resin composition of the present invention may be produced by, forexample, after preliminarily mixing each component, mixing with the useof a three-roll mill and defoaming under vacuum.

A method of producing a semiconductor device using a resin compositionof the present invention may be conducted in conventional manners. Forexample, after dispensing a resin composition on a certain portion of alead frame by means of a commercially available die bonder, a chip ismounted followed by heat-curing. Then, it is subject to wire-bonding andto transfer molding with the use of an epoxy molding compound, thereby,a semiconductor device is produced.

Hereafter, among various compositions which are combinations ofessential components such as the filler (A), the compound (B) and thethermal radical initiator (C), and optional components, the followingfirst to sixth composition systems are exemplified as particularlypreferable.

(1) A First Composition System

A first composition system is a composition comprising at least thefiller (A), the compound (B), the thermal radical initiator (C) and thecompound (D), and substantially not containing a photo polymerizationinitiator.

Among the first composition system, a composition which further containsone or more silane-based coupling agents (J) is also preferable.

(2) A Second Composition System

A second composition system is a composition comprising at least thefiller (A), the compound (B), the thermal radical initiator (C), thecompound (D) and a combination of the compound (L) and the compound (M),and substantially not containing a photo polymerization initiator.

Among the second composition system, a composition which furthercontains one or more silane-based coupling agents (J) is alsopreferable.

(3) A Third Composition System

A third composition system is a composition comprising at least thefiller (A), the compound (B), the thermal radical initiator (C) and theacrylic ester compound (E), and substantially not containing a photopolymerization initiator.

Among the third composition system, a composition which further containsone or more silane-based coupling agents (J) is also preferable.

(4) A Forth Composition System

A forth composition system is a composition comprising the filler (A),the compound (B), the thermal radical initiator (C) and the acrylamidecompound (F), and substantially not containing a photo polymerizationinitiator.

Among the forth composition system, a composition which further containsone or more silane-based coupling agents (J) is also preferable.

(5) A Fifth Composition System

A fifth composition system is a composition comprising the filler (A),the compound (B), the thermal radical initiator (C) and the allyl estercompound (G), and substantially not containing a photo polymerizationinitiator.

The fifth composition system preferably contains 20 to 60 wt % of theallyl ester compound (G) with respect to the total amount of thecompound (B) and the allyl ester compound (G). If the ratio of the allylester compound (G) excessively increases, curability may deteriorate.

Among the fifth composition system, a composition which further containsone or more silane-based coupling agents (J) is also preferable.

(6) A Sixth Composition System

A sixth composition system is a composition comprising the filler (A),the compound (B), the thermal radical initiator (C), the compound (H)and the reactive diluent (I), and substantially not containing a photopolymerization initiator.

Among the sixth composition system, a composition which further containsone or more silane-based coupling agents (J) is also preferable.

EXAMPLES

The following experimental examples further describe the above-mentionedfirst to sixth composition systems of the present invention.

Firstly, experimental examples of the first composition system(Experimental example series A) are hereinafter described. Thecompounding ratio is in “part by weight”.

Examples A1 to A4, Comparative Examples A1 to A3

As the compound (B), polyether-based bismaleimide acetic ester (LUMICUREMIA-200, manufactured by DAINIPPON INK & CHEMICALS, INC., a compoundwherein R² is —C₂H₂— and R³ is —CH₂— in the formula (2), and X¹ is —O—and R¹ is —C₄H₈— in the formula (1), hereafter referred as “compound 1”)was used. As the compound (D), polypropylene glycol dimethacrylate(BLEMMER PDP-400, manufactured by NOF Corporation, hereafter referred as“compound 2”) and polytetramethylene glycol dimethacrylate (BLEMMERPDT-800, manufactured by NOF Corporation, hereafter referred as“compound 3”) were used. As the thermal radical initiator (C), dicumylperoxide (decomposition temperature: 126° C. in rapid heating test,Percumyl D, manufactured by NOF Corporation, hereafter referred as“initiator”) was used. As the filler (A), silver powder in a flake-likeform having an average particle size of 3 μm and a maximum particle sizeof 20 μm (hereafter referred as “silver powder”) was used. Also, laurylacrylate (Light Ester LA, manufactured by KYOEISHA CHEMICAL Co., LTD.,hereafter referred as “diluent”) and a silane coupling agent having amethacryl group (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.,hereafter referred as “methacryl silane”) were used.

These compounds were compounded in combination as shown in Table 1 andkneaded by means of the three-roll mill followed by defoaming, thusresin compositions were obtained.

In Comparative example A1, polyethylene glycol dimethacrylate (BLEMMERPDE-400, manufactured by NOF Corporation, hereafter referred as“compound 4”) was used. In Comparative example A3, diglycidyl bisphenolA obtainable by reacting bisphenol A and epichlorohydrin (epoxyequivalent: 180, liquid at room temperature, hereafter referred as“bis-A-epoxy”), cresyl glycidyl ether (epoxy equivalent: 185, hereafterreferred as “CGE”), phenol novolac resin (hydroxyl equivalent: 104,softening point: 85° C., hereafter referred as “PN”),2-phenyl-4,5-dihydroxymethylimidazole (product name: Curezole,manufactured by Shikoku Chemicals Corporation, hereafter referred as“2PHZ”) and a silane coupling agent having a glycidyl group (KBM-403E,manufactured by Shin-Etsu Chemical Co., Ltd., hereafter referred as“epoxy silane”) were used.

The obtained resin compositions were evaluated in the following manner.The evaluation results are shown in Table 1.

TABLE 1 Example Comparative example A1 A2 A3 A4 A1 A2 A3 Compound 1 7.89.7 7.8 7.8   7.8 Compound 2 11.7 Compound 3 11.7 9.7 9.7 19.4 Compound4   11.7 Diluent 1.9 Initiator 0.4 0.4 0.4 0.4   0.4  0.4 Silver powder80.0 80.0 80.0 80.0   80.0 80.0 75.0 Bis-A-epoxy 16.1 CGE  6.9 PN  1.12PHZ  0.7 Methacryl silane 0.2 0.2 0.2 0.2   0.2  0.2 Epoxy silane  0.2Viscosity Initial value (Pa · s) 18.4 20.4 16.4 17.8   16.8 15.4 21.6After 48 hours (Pa · s) 18.6 20.8 16.8 17.2   17.0 15.2 21.8 Viscosityincreasing rate 1% 2% 2% −3% 1% −1% 1% Adhesion strength 30 secondscuring After curing 45 45 41 54 51 22   16   (N/chip) (hot plate) AfterPCT 35 40 32 44 24 8  3  60 minutes curing After curing 50 52 48 50 4831   37   (oven) After PCT 34 38 33 34 20 15   18   Soder crackresistance Delaminated area (%) <10 <10 <10 <10   50< 50<  50< Comprehensive evaluation ∘ ∘ ∘ ∘ x x x

Evaluation Method of Experimental Example Series A

(1) Viscosity

Using an E type viscometer (3° cone), values were measured at 2.5 rpm at25° C. just after producing a resin composition and after leaving for 48hours at 25° C. A measured result having viscosity of 15 to 25 Pa·s justafter production and viscosity increasing rate after 48 hours of lessthan 20% was evaluated to have passed the criteria. A unit of viscosityis “Pa·s” and a unit of viscosity increasing rate is “%”.

(2) Adhesion Strength

A 6×6 mm silicon chip was mounted on a silver plated copper frame usingthe obtained resin composition and cured on a hot plate of 200° C. for30 seconds and in an oven of 150° C. for 60 minutes respectively. Aftercuring and PCT process (121° C., 100%, 72 hours), hot die shear strengthat 260° C. was measured by means of the automatic adhesion strengthtester. A measured result having hot die shear strength at 260° C. of 30N/chip or more was evaluated to have passed the criteria. A unit ofadhesion strength is “N/chip”.

(3) Solder Crack Resistance

The following lead frame and the following silicon chip were bonded bycuring under the following curing condition using the obtained resincompositions followed by molding by an epoxy molding compound (SumikonEME-7026, manufactured by Sumitomo Bakelite Company Limited). Thepackage was subject to a moisture absorption treatment for 192 hours inan atmosphere of 60° C. and 60% relative humidity, and then to an IRreflow treatment (260° C., 10 seconds, three times of reflow). Then, thedegree of delamination of packages after the treatments was measured bymeans of the scanning acoustic microscope detector (through scan mode).A measured result having a delaminated area of a die attach portion ofless than 10% was evaluated to have passed the criteria. A unit ofdelaminated area is “%”.

Package: QFP (14×20×2.0 mm)

Lead frame: silver spot plated copper frame

Chip size: 6×6 mm

Curing condition of a resin composition: a hot plate at 200° C. for 60seconds

Next, experimental examples of the second composition system(Experimental example series B) are hereinafter described. Thecompounding ratio is in “part by weight”.

Examples B1 to B4, Comparative Examples B1 to B4

As the compound (B), polyether-based bismaleimide acetic ester (LUMICUREMIA-200, manufactured by DAINIPPON INK & CHEMICALS, INC., a compoundwherein R² is —C₂H₂— and R³ is —CH₂— in the formula (2), and X¹ is —O—and R¹ is —C₄H₈— in the formula (1), hereafter referred as “compound 1”)was used. As the compound (D), polypropylene glycol dimethacrylate(BLEMMER PDP-400, manufactured by NOF Corporation, hereafter referred as“compound 2”) and polytetramethylene glycol dimethacrylate (BLEMMERPDT-800, manufactured by NOF Corporation, hereafter referred as“compound 3”) were used. As the compound (L) containing a glycidylgroup, polytetramethylene glycol diglycidyl ether (ED-612, manufacturedby Asahi Denka Co., Ltd., hereafter referred as “compound 4”) andpolypropylene glycol diglycidyl ether (ED-506, manufactured by AsahiDenka Co., Ltd., hereafter referred as “compound 5”) were used. As thecompound (M) which reacts with a glycidyl group,2-phenyl-4,5-dihydroxymethylimidazole (product name: Curezole,manufactured by Shikoku Chemicals Corporation, hereafter referred as“2PHZ”) was used. As the thermal radical initiator (C), dicumyl peroxide(decomposition temperature: 126° C. in rapid heating test, Percumyl D,manufactured by NOF Corporation, hereafter referred as “initiator”) wasused. As the filler (A), silver powder in a flake-like form having anaverage particle size of 3 μm and a maximum particle size of 20 μm(hereafter referred as “silver powder”) was used. Also, lauryl acrylate(Light Ester LA, manufactured by KYOEISHA CHEMICAL Co., LTD., hereafterreferred as “diluent”), a silane coupling agent having a methacryl group(KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd., hereafterreferred as “methacryl silane”) and a silane coupling agent having aglycidyl group (KBM-403E, manufactured by Shin-Etsu Chemical Co., Ltd.,hereafter referred as “epoxy silane”) were used.

These compounds were compounded as shown in Table 2 and kneaded by meansof the three-roll mill followed by defoaming, thus obtained resincompositions.

In Comparative examples B1 and B2, polyethylene glycol dimethacrylate(BLEMMER PDE-400, manufactured by NOF Corporation, hereafter referred as“compound 6”) was used. In Comparative example B4, diglycidyl bisphenolA obtained by reacting bisphenol A and epichlorohydrin (epoxyequivalent: 180, liquid at room temperature, hereafter referred as“bis-A-epoxy”), cresyl glycidyl ether (epoxy equivalent: 185, hereafterreferred as “CGE”) and phenol novolac resin (hydroxyl equivalent: 104,softening point: 85° C., hereafter referred as “PN”) were used.

The obtained resin compositions were evaluated in the following manner.The evaluation results are shown in Table 2.

TABLE 2 Example Comparative example B1 B2 B3 B4 B1 B2 B3 B4 Compound 15.8 5.8 5.8 5.8 5.8  7.7 Compound 2 5.8 5.8 Compound 3 11.6 5.8 5.8 9.617.4 Compound 4 1.9 1.9 1.9 1.9  1.9 Compound 5 1.9 Compound 6 11.6 11.6 Diluent 1.9 Initiator 0.4 0.4 0.4 0.4 0.4  0.4  0.4 Silver powder80.0 80.0 80.0 80.0 80.0  80.0 80.0 75.0 Bis-A-epoxy 16.1 CGE  6.9 PN 1.1 2PHZ 0.1 0.1 0.1 0.1 0.1  0.1  0.1  0.7 Methacryl silane 0.2 0.20.2 0.2 0.2  0.2  0.2 Epoxy silane 0.06 0.06 0.06 0.06  0.06  0.06  0.06 0.23 Viscosity Initial value (Pa · s) 19.6 18.0 17.2 15.4 16.0  18.615.8 21.6 After 48 hours (Pa · s) 20.0 18.4 17.8 15.6 15.8  18.4 16.021.8 Viscosity increasing rate 2% 2% 3% 1% −1% −1% 1% 1% Adhesionstrength 30 seconds curing After curing 50 52 48 54 50   12   8  22  (N/chip) (hot plate) After PCT 46 45 44 48 22   2  1  5  60 minutescuring After curing 56 54 50 54 52   8  10   56   (oven) After PCT 42 4042 44 25   1  2  20   Soder crack resistance Delaminated area (%) <10<10 <10 <10 50<    50<  50<  50<  Comprehensive evaluation ∘ ∘ ∘ ∘ x x xx

Evaluation Method of Experimental Example Series B

(1) Viscosity

Using an E type viscometer (3° cone), values were measured at 2.5 rpm at25° C. just after producing a resin composition and after leaving for 48hours at 25° C. A measured result having viscosity of 15 to 25 Pa·s justafter production and viscosity increasing rate after 48 hours of lessthan 20% was evaluated to have passed the criteria. A unit of viscosityis “Pa·s” and a unit of viscosity increasing rate is “%”.

(2) Adhesion Strength

A 6×6 mm silicon chip was mounted on a ring plated copper frame (silverplated only on inner lead part) using the obtained resin compositionsand cured on a hot plate of 200° C. for 30 seconds and in an oven of150° C. for 60 minutes respectively. After curing and PCT process (121°C., 100%, 72 hours), hot die shear strength at 260° C. was measured bymeans of the automatic adhesion strength tester. A measured resulthaving hot die shear strength at 260° C. of 30 N/chip or more wasevaluated to have passed the criteria. A unit of adhesion strength is“N/chip”.

(3) Solder Crack Resistance

The following lead frame and the following silicon chip were bonded bycuring under the following curing condition with the use of the obtainedresin compositions followed by molding by an epoxy molding compound(Sumikon EME-7026, manufactured by Sumitomo Bakelite Company Limited).The package was subject to a moisture absorption treatment for 192 hoursin an atmosphere of 60° C. and 60% relative humidity, and then to an IRreflow treatment (260° C., 10 seconds, three times of reflow). Then, thedegree of delamination of packages after the treatments was measured bymeans of the scanning acoustic microscope detector (through scan mode).A measured result having a delaminated area of a die attach portion ofless than 10% was evaluated to have passed the criteria. A unit ofdelaminated area is “%”.

Package: QFP (14×20×2.0 mm)

Lead frame: ring plated copper frame (silver plated only on inner leadpart)

Chip size: 6×6 mm

Curing condition of a resin composition: a hot plate at 200° C. for 60seconds

Next, experimental examples of the third composition system(Experimental example series C) are hereinafter described. Thecompounding ratio is in “part by weight”.

Example C1 to C4

(1) Synthesis of a Maleimide of Amino Acid

(1-1) Maleimide Acetic Acid

After 120 g of maleic anhydride and 500 g of toluene were charged in aseparable flask and refluxed for one hour while stirring to removemoisture in the system by means of the Dean-Stark trap, the flask wascooled to room temperature followed by dropping a liquid wherein 75 g ofglycine (aminoacetic acid) was solved in 200 g of acetonitrile in theflask placed in an ice bath for 60 minutes while introducing drynitrogen, and then the liquid was stirred at room temperature for 23hours.

Next, the liquid was stirred under reflux for 8 hours while removing thegenerated moisture by the Dean-Stark trap. The obtained liquid phase wassubject to separation for washing using pure water for 5 times followedby removing a solvent using the evaporator and the vacuum dryer, thusobtained a product. The obtained product was brown crystal and had yieldof about 150 g. Formation of maleimide groups was confirmed by NMR andIR.

(1-2) Maleimide Caproic Acid

After 120 g of maleic anhydride and 500 g of toluene were charged in aseparable flask and refluxed for one hour while stirring to removemoisture in the system by means of the Dean-Stark trap, the flask wascooled to room temperature followed by dropping a liquid wherein 131 gof 6-aminocaproic acid was solved in 200 g of acetonitrile in the flaskplaced in an ice bath for 60 minutes while introducing dry nitrogen, andthen the liquid was stirred at room temperature for 23 hours.

Next, the liquid was stirred under reflux for 8 hours while removing thegenerated moisture by the Dean-Stark trap. The obtained liquid phase wassubject to separation for washing using pure water for 5 times followedby removing a solvent using the evaporator and the vacuum dryer, thusobtained a product. The obtained product was brown crystal and had yieldof about 195 g. Formation of maleimide groups was confirmed by NMR andIR.

(2) Reaction of a Maleimide of Amino Acid and Diol

(2-1) Reaction of Maleimide Acetic Acid and Polypropylene Glycoldiol

After 62 g of maleimide acetic acid synthesized in (1-1), 90 g ofpolypropylene glycoldiol (repeating number of about 7, Uniol D-400,manufactured by NOF Corporation), 500 g of toluene and 3.4 g ofparatoluene sulfonic acid were charged in a separable flask and refluxedfor 16 hours while stirring. The generated moisture was removed outsidethe system by the Dean-Stark trap. After reaction, the obtained liquidphase was subject to separation for washing using 70° C. distilled waterfor 3 times and distilled water at room temperature for 2 times. Theobtained solvent layer was dried using the evaporator and the vacuumdryer, thus obtained a product. The obtained product was brown liquidand had yield of about 130 g. Formation of ester bonds and disappearanceof carboxyl groups were confirmed by NMR and IR. The obtained product isa bismaleimide compound (B′) represented by the formula (3) wherein X²is —O—, R⁴ is —H, R⁵ has 1 carbon, R⁶ has 3 carbons and “n” is about 6,which is hereafter referred as “compound B1”.

(2-2) Reaction of Maleimide Acetic Acid and Polybutylene Glycoldiol

After 62 g of maleimide acetic acid synthesized in (1-1), 110 g ofpolybutylene glycoldiol (repeating number of about 7, Uniol PB-500,manufactured by NOF Corporation), 500 g of toluene and 3.4 g ofparatoluene sulfonic acid were charged in a separable flask and obtaineda product similarly as (2-1). The obtained product was brown liquid andhad yield of about 150 g. Formation of ester bonds and disappearance ofcarboxyl groups were confirmed by NMR and IR. The obtained product is abismaleimide compound (B′) represented by the formula (3) wherein X² is—O—, R⁴ is —H, R⁵ has 1 carbon, R⁶ has 4 carbons and “n” is about 6,which is hereafter referred as “compound B2”.

(2-3) Reaction of Maleimide Caproic Acid and Polypropylene Glycoldiol

After 84 g of maleimide caproic acid synthesized in (1-2), 90 g ofpolypropylene glycoldiol (repeating number of about 7, Uniol D-400,manufactured by NOF Corporation), 500 g of toluene and 3.4 g ofparatoluene sulfonic acid were charged in a separable flask and obtaineda product similarly as (2-1). The obtained product was brown liquid andhad yield of about 150 g. Formation of ester bonds and disappearance ofcarboxyl groups were confirmed by NMR and IR. The obtained product is abismaleimide compound (B′) represented by the formula (3) wherein X² is—O—, R⁴ is —H, R⁵ has 5 carbons, R⁶ has 3 carbons and “n” is about 6,which is hereafter referred as “compound B3”.

(2-4) Reaction of Maleimide Caproic Acid and Polybutylene Glycoldiol

After 84 g of maleimide caproic acid synthesized in (1-2), 110 g ofpolybutylene glycoldiol (repeating number of about 7, Uniol PB-500,manufactured by NOF Corporation), 500 g of toluene and 3.4 g ofparatoluene sulfonic acid were charged in a separable flask and obtaineda product similarly as (2-1). The obtained product was brown liquid andhad yield of about 167 g. Formation of ester bonds and disappearance ofcarboxyl groups were confirmed by NMR and IR. The obtained product is acompound represented by the formula (3) wherein X² is —O—, R⁴ is —H, R⁵has 5 carbons, R⁶ has 4 carbons and “n” is about 6, which is hereafterreferred as “compound B4”.

(3) Reaction of Acrylic Acid and Polybutylene Glycoldiol

After 35 g of acrylic acid, 104 g of polybutylene glycoldiol (repeatingnumber of about 7, Uniol PB-500, manufactured by NOF Corporation), 500 gof toluene and 3.4 g of paratoluene sulfonic acid were charged in aseparable flask and refluxed for 16 hours while stirring. The generatedmoisture was removed outside the system by the Dean-Stark trap. Afterreaction, the obtained liquid phase was subject to separation forwashing using 70° C. distilled water for 3 times and distilled water atroom temperature for 2 times. The obtained solvent layer was dried usingthe evaporator and the vacuum dryer, thus obtained a product. Theobtained product was light brown liquid and had yield of about 120 g.Formation of ester bonds and disappearance of carboxyl groups wereconfirmed by NMR and IR. The obtained product is hereafter referred as“compound X”.

As the filler (A), silver powder in a flake-like form having an averageparticle size of 8 μm and a maximum particle size of 30 μm (hereafterreferred as “silver powder”) was used. As the compound (B), thecompounds B1 to B4 were used. As the acrylic ester compound (E),2-hydroxypropyl methacrylate (the formula (5) wherein R⁸ is a methylgroup, R⁹ is a methyl group, x=1, y=1 and z=1, Light Ester HOP,manufactured by KYOEISHA CHEMICAL Co., LTD., hereafter referred as“compound E1”) and glycerol dimethacrylate (the formula (5) wherein R⁸is a methyl group, x=2, y=1 and z=0, Light Ester G-101P, manufactured byKYOEISHA CHEMICAL Co., LTD., hereafter referred as “compound E2”) wereused. As the thermal radical initiator (C), dicumyl peroxide(decomposition temperature: 126° C. in rapid heating test, Percumyl D,manufactured by NOF Corporation, hereafter referred as “initiator”) wasused.

Also, the compound X was used, and as silane coupling agents, a silanecoupling agent having a tetrasulfide bond (A-1289, manufactured byNippon Unicar Company Limited, hereafter referred as “coupling agent 1”)and a silane coupling agent having a glycidyl group (KBM-403E,manufactured by Shin-Etsu Chemical Co., Ltd., hereafter referred as“coupling agent 2”) were used.

These compounds were compounded in combination as shown in Table 3 andkneaded by means of the three-roll mill followed by defoaming, thus aresin composition was obtained.

Example C5

As a vinyl compound in liquid form, the compound X was used.

Example C6

As a compound having a glycidyl group, diglycidyl bisphenol A obtainableby reacting bisphenol A and epichlorohydrin (epoxy equivalent: 180,liquid at room temperature, hereafter referred as “compound Y1”) and areacted product of 2-methylimidazole and 2,4-diamino-6-vinyltriazine(product name: Curezole 2MZ-A, manufactured by Shikoku ChemicalsCorporation, hereafter referred as “compound Y2”) were used.

Comparative Examples C1 and C2

Each of the compounds is compounded in ratio as shown in Table 3, thusobtained resin compositions similarly to Example C1.

Comparative Example C3

1,6-Hexandiol dimethacrylate (Light Ester 1, 6HX, manufactured byKYOEISHA CHEMICAL Co., LTD., hereafter referred as “compound Z1”) wasused.

Comparative Example C4

2,2-bis[4-(4-maleimidephenoxy)phenyl]propane (BMI-80, manufactured by K.I CHEMICAL INDUSTRY CO., LTD.) was used. As BMI-80 is in solid form,BMI-80 and dimethylformamide (DMF) were mixed by weight ratio of 1:1 andused in solution form (hereafter referred as “compound Z2”).

The obtained resin compositions were evaluated in the following manner.The evaluation results are shown in Table 3.

TABLE 3 Example Comparative example C1 C2 C3 C4 C5 C6 C1 C2 C3 C4 Silverpowder 80.0 80.0 80.0 80.0 80.0 80.0  80.0   80.0 80.0   80.0 CompoundB1 11.54 9.60 11.54 Compound B2 11.54 9.62 Compound B3 11.54 Compound B411.54 Compound Z2   14.63 Compound E1 3.85 3.85 3.85 3.85 1.92 3.20  9.62    3.77    2.44 Compound E2 3.85 3.85 3.85 3.85 1.92 3.20   9.62   3.77    2.44 Compound Z1 7.69 Compound X 5.77 Initiator 0.38 0.380.38 0.38 0.38 0.32   0.38    0.19 0.38    0.24 Compound Y1 3.20   11.32Compound Y2 0.16    0.57 Coupling agent 1 0.29 0.29 0.29 0.29 0.29 0.24  0.29    0.28 0.29    0.18 Coupling agent 2 0.10 0.10 0.10 0.10 0.100.08   0.10    0.09 0.10    0.06 Adhesion strength After curing N/chip50 50 48 52 50 46 10  40 42 32 silver spot After moisture absorbtionN/chip 40 45 45 46 44 41 2 20 35 24 Adhesion strength After curingN/chip 40 42 41 40 40 44 5 62 34 23 silver ring After moistureabsorbtion N/chip 34 35 38 35 38 40 3 28 30 18 Adhesion strength Aftercuring N/chip 44 50 44 46 48 46 15  30 40 35 Ni—Pd After moistureabsorbtion N/chip 40 42 39 44 42 40 2 18 32 22 Bleeding Silver spot μm<10 <10 <10 <10 <10 <10 <10    50 50 <10   Silver ring μm 20 20 20 20 40<10 20  20 100 <10   Ni—Pd μm 30 30 30 30 30 40 90  100  300 <10  Temperature After curing % <10 <10 <10 <10 <10 <10 50< <10   <10 20cycle resistance After moisture absorbtion % <10 <10 <10 <10 <10 <10 50<  50< <10   50< Delaminated area Warpage μm <20 <20 <20 <20 <20 <20<20    30 <20 50 Reflow resistance Delaminated area % <10 <10 <10 <10<10 <10 50<   50< <10   50< Comprehensive evaluation ∘ ∘ ∘ ∘ ∘ ∘ x x x x

Evaluation Method of Experimental Example Series C

(1) Adhesion Strength

A 6×6 mm silicon chip was mounted on a copper frame using the obtainedresin composition and cured in an oven of 150° C. for 30 minutes. Threekinds of copper frames were used, namely, silver spot plating (silverplated on a die pad portion), silver ring plating (die pad portion ismade of copper) and Ni—Pd/Au plating. After curing and the moistureabsorption treatment (85° C., 85%, 72 hours), hot die shear strength at260° C. was measured by means of the automatic adhesion strength tester.A measured result having hot die shear strength at 260° C. of 30 N/chipor more was evaluated to have passed the criteria. A unit of adhesionstrength is “N/chip”.

(2) Bleeding

Bleeding of the cured products was observed by means of the opticalmicroscope before the above-mentioned adhesion strength measurement. Themaximum length of bleeding on each test piece was defined as bleeding. Ameasured result having bleeding length of 50 μm or less was evaluated tohave passed the criteria. A unit of bleeding is “μm”.

(3) Temperature Cycle Resistance

A 15×15×0.5 mm silicon chip was mounted on a Ni plated copper heatspreader using the obtained resin compositions and cured in an oven of150° C. for 30 minutes. After curing and the temperature cycle process(−65° C.

150° C., 100 cycles), delamination was measured by means of the scanningacoustic microscope detector (through scan mode). A measured resulthaving delaminated area of less than 10% was evaluated to have passedthe criteria. A unit of delaminated area is “%”.

(4) Warpage and Reflow Resistance

The following substrate (lead frame) and the following silicon chip werebonded by curing at 150° C. for 30 minutes using resin compositionsshown in Table 3. After curing, warpage of 10 mm on diagonal of chipsurface was measured by means of the surface roughness meter. A unit ofwarpage is “μm”. A measured result having warpage of 20 μm or less wasevaluated to have passed the criteria. Also, similarly die bonded leadframe was molded using a molding compound (Sumikon EME-7026,manufactured by Sumitomo Bakelite Company Limited). The package wassubject to a moisture absorption treatment for 192 hours in anatmosphere of 85° C. and 60% relative humidity, and then to an IR reflowtreatment (260° C., 10 seconds, three times of reflow). The degree ofdelamination after the treatments was measured by means of the scanningacoustic microscope detector (through scan mode). A measured resulthaving a delaminated area of a die attach portion of less than 10% wasevaluated to have passed the criteria. A unit of delaminated area is“%”.

Package: QFP (14×20×2.0 mm)

Lead frame: silver spot plated copper frame

Chip size: 9×9 mm

Curing condition of a resin composition: in an oven at 150° C. for 30minutes

Next, experimental examples of the forth composition system(Experimental example series D) are hereinafter described. Thecompounding ratio is in “part by weight”.

Examples D1, D2 and D3

(1) Preparation of Compound (1)

67 g of polytetramethylene glycoldiol (repeating unit number of about 9measured by NMR, PTMG650, manufactured by Mitsubishi ChemicalCorporation) and 24 g of succinic anhydride (reagent) were stirred witha mixed solvent of acetonitrile/toluene (weight ratio 1:3) under refluxfor four hours followed by separation for washing using ion-exchangewater for 5 times. After collecting the acetonitrile/toluene layer,dehydration by means of the Dean-Stark trap under reflux and cooling toroom temperature, 25 g of 2-hydroxylethylacrylamide (HEAA, manufacturedby Kohjin Co., Ltd., hereafter referred as “HEAA”) was added followed bydropping dicyclocarbodiimide/dimethylaminopyridine in ethyl acetatesolution while stirring. After dropping, reaction was performed at roomtemperature for 16 hours.

After reaction, separation for washing was performed using ion-exchangewater for 5 times. Thereafter, the organic solvent layer was filtratedto remove solid content followed by removing a solvent using theevaporator and the vacuum dryer, thus obtained a compound. The obtainedcompound was used for the following tests and referred hereafter as“compound (1)”. The obtained compound had yield of about 85% and astyrene standard molecular weight by GPC of about 1,000. The compound(1) is a compound wherein X⁴ is —O— and R¹⁰ has 4 carbons and therepeating number of about 9 in the formula (6), and R¹¹ is —H in theformula (7).

(2) Preparation of Compound (2)

70 g of polytetrbutylene glycoldiol (average molecular weight of 700,Uniol PB-700, manufactured by NOF Corporation) and 24 g of succinicanhydride (reagent) were stirred with a mixed solvent ofacetonitrile/toluene (weight ratio 1:3) under reflux for four hoursfollowed by separation for washing using ion-exchange water for 5 times.After collecting the acetonitrile/toluene layer, dehydration by means ofthe Dean-Stark trap under reflux and cooling to room temperature, 25 gof 2-hydroxylethylacrylamide (HEAA, manufactured by Kohjin Co., Ltd.,hereafter referred as “HEAA”) was added followed by droppingdicyclocarbodiimide/dimethylaminopyridine in ethyl acetate solutionwhile stirring. After dropping, reaction was performed at roomtemperature for 16 hours.

After reaction, separation for washing was performed using ion-exchangewater for 5 times. Thereafter, the organic solvent layer was filtratedto remove solid content followed by removing a solvent using theevaporator and the vacuum dryer, thus obtained a compound. The obtainedcompound was used for the following tests and referred hereafter as“compound (2)”. The obtained compound had yield of about 87%, productionof ester was confirmed by NMR and IR and styrene standard molecularweight by GPC was about 1,000. The compound (2) is a compound wherein X⁴is —O— and R¹⁰ has 4 carbons and the repeating number of about 9 in theformula (6), and R¹¹ is —H in the formula (7).

As the acrylamide compound (F), the above-mentioned compound (1) andcompound (2) were used. As the compound (B), polyether-basedbismaleimide acetic ester (LUMICURE MIA-200, manufactured by DAINIPPONINK & CHEMICALS, INC., a compound wherein R² is —C₂H₂— and R³ is —CH₂—in the formula (2), and X¹ is —O— and R¹ is —C₄H₈— in the formula (1),hereafter referred as “compound (3)”) was used. As the reactive diluent(I), lauryl acrylate (Light Ester LA, manufactured by KYOEISHA CHEMICALCo., LTD., hereafter referred as “diluent”) was used. As the thermalradical initiator (C), dicumyl peroxide (decomposition temperature: 126°C. in rapid heating test, Percumyl D, manufactured by NOF Corporation,hereafter referred as “initiator”) was used. As the silane couplingagent, a silane coupling agent having a tetrasulfide bond (A-1289,manufactured by Nippon Unicar Company Limited, hereafter referred as“coupling agent 1”) and a silane coupling agent having a glycidyl group(KBM-403E, manufactured by Shin-Etsu Chemical Co., Ltd., hereafterreferred as “coupling agent 2”) were used. As the filler (A), silverpowder in a flake-like form having an average particle size of 5 μm anda maximum particle size of 30 μm (hereafter referred as “silver powder”)was used.

These components were compounded in combination as shown in Table 4 andkneaded by means of the three-roll mill followed by defoaming, thusresin compositions were obtained. The compounding ratio is in “part byweight”.

Comparative Examples D1 and D2

Each component was compounded in ratio as shown in Table 4, andsimilarly to Example D1, resin compositions were obtained. InComparative example D1, diacrylate of tetramethyleneoxide (NK esterA-PTMG 65, manufactured by SHIN-NAKAMURA CHEMICAL CO., LTD., hereafterreferred as “compound (4)”) was used.

The obtained resin compositions were evaluated in the following manner.The evaluation results are shown in Table 4.

TABLE 4 Comparative Example example D1 D2 D3 D1 D2 Silver powder 85.0085.00 85.00 85.00 85.00 Compound (1) 5.74 5.74 Compound (2) 5.74 5.74Compound (3) 4.31 4.31 4.31 Compound (4) 5.74 11.48 LA 4.31 4.31 2.874.31 2.87 Initiator 0.29 0.29 0.29 0.29 0.29 Coupling agent 1 0.29 0.290.29 0.29 0.29 Coupling agent 2 0.07 0.07 0.07 0.07 0.07 Adhesion Aftercuring N/chip 64 62 58 48 35 strength After N/chip 56 58 42 35 20moisture absorbtion Warpage μm <20 <20 <20 <20 <20 Reflow Delaminated %<10 <10 <10 20 100 resistance area Comprehensive evaluation ∘ ∘ ∘ x x

Evaluation Method of Experimental Example Series D

(1) Adhesion Strength

A 6×6 mm silicon chip was mounted on a silver plated copper frame usingthe obtained resin compositions and cured in an oven of 150° C. for 15minutes. After curing and the moisture absorption treatment (85° C.,85%, 72 hours), hot die shear strength at 260° C. was measured by meansof the automatic adhesion strength tester. A measured result having hotdie shear strength at 260° C. of 30 N/chip or more was evaluated to havepassed the criteria. A unit of adhesion strength is “N/chip”.

(2) Warpage and Reflow Resistance

The following substrate (lead frame) and the following silicon chip werebonded by curing at 150° C. for 15 minutes using resin compositionsshown in Table 4. After curing, warpage of 10 mm on diagonal of chipsurface was measured by means of the surface roughness meter. A unit ofwarpage is “μm”. A measured result having warpage of 20 μm or less wasevaluated to have passed the criteria. Also, similarly die bonded leadframe was molded using a molding compound (Sumikon EME-7026,manufactured by Sumitomo Bakelite Company Limited). The package wassubject to a moisture absorption treatment for 192 hours in anatmosphere of 85° C. and 60% relative humidity, and then to an IR reflowtreatment (260° C., 10 seconds, three times of reflow). The degree ofdelamination after the treatments was measured by means of the scanningacoustic microscope detector (through scan mode). A measured resulthaving a delaminated area of a die attach portion of less than 10% wasevaluated to have passed the criteria. A unit of delaminated area is“%”.

Package: QFP (14×20×2.0 mm)

Lead frame: silver spot plated copper frame

Chip size: 9×9 mm

Curing condition of a resin composition: in an oven at 150° C. for 30minutes

Next, experimental examples of the fifth composition system(Experimental example series E) are hereinafter described. Thecompounding ratio is in “part by weight”.

Examples E1, E2 and E3

As the compound (B), polyether-based bismaleimide acetic ester (LUMICUREMIA-200, manufactured by DAINIPPON INK & CHEMICALS, INC., a compoundwherein R² is —C₂H₂— and R³ is —CH₂— in the formula (2), and X¹ is —O—and R¹ is —C₄H₈— in the formula (1), hereafter referred as “compound 1”)was used. As the allyl ester compound (G), an allyl ester compound(allyl ester resin DA101, manufactured by Showa, a compound wherein R¹³is a cyclohexane group in the formula (9), hereafter referred as“compound 2”) was used. As the filler (A), silver powder in a flake-likeform having an average particle size of 5 μm and a maximum particle sizeof 30 μm (hereafter referred as “silver powder”) was used. As thethermal radical initiator (C), dicumyl peroxide (decompositiontemperature: 126° C. in rapid heating test, Percumyl D, manufactured byNOF Corporation, hereafter referred as “initiator”) was used. Also, asilane coupling agent having a methacryl group (KBM-503, manufactured byShin-Etsu Chemical Co., Ltd., hereafter referred as “methacryl silane”)was used.

These components were compounded in combination as shown in Table 5 andkneaded by means of the three-roll mill followed by defoaming, thusresin compositions were obtained. The compounding ratio is in “part byweight”.

Comparative Example E1

Each component was compounded in ratio as shown in Table 5, andsimilarly to Example E1, a resin composition was obtained.

The obtained resin composition was evaluated in the following manner.The evaluation result is shown in Table 5.

TABLE 5 Comparative Example example E1 E2 E3 E1 Silver powder 80.0080.00 80.00 80.00 Compound 1 14.56 11.65 8.74 Compound 2 4.85 7.77 10.6819.42 Initiator 0.39 0.39 0.39 0.39 Methacryl silane 0.19 0.19 0.19 0.19Adhesion After curing N/chip 55 55 50 20 strength 1 Adhesion Aftercuring N/chip 60 62 60 18 strength 2 Warpage μm <20 <20 <20 <20 ReflowDelaminated % <10 <10 <10 100 resistance area Comprehensive evaluation ∘∘ ∘ x

Evaluation Method of Experimental Example Series E

(1) Adhesion Strength 1

A 6×6 mm silicon chip was mounted on a silver plated copper frame usingthe obtained resin composition and cured in an oven of 150° C. for 30minutes. Hot die shear strength at 260° C. was measured by means of theautomatic adhesion strength tester. A measured result having hot dieshear strength at 260° C. of 40 N/chip or more was evaluated to havepassed the criteria. A unit of adhesion strength is “N/chip”.

(2) Adhesion Strength 2

A 6×6 mm silicon chip was mounted on a heat spreader made of copperhaving black oxide surface using the obtained resin compositions andcured in an oven of 150° C. for 30 minutes. Hot die shear strength at260° C. was measured by means of the automatic adhesion strength tester.A measured result having hot die shear strength at 260° C. of 40 N/chipor more was evaluated to have passed the criteria. A unit of adhesionstrength is “N/chip”.

(3) Warpage and Reflow Resistance

The following substrate (lead frame) and the following silicon chip werebonded by curing at 150° C. for 15 minutes using resin compositionsshown in Table 5. After curing, warpage of chip surface was measured bymeans of the surface roughness meter. A unit of warpage is “μm”. Ameasured result having warpage of 20 μm or less was evaluated to havepassed the criteria. Also, similarly die bonded lead frame was moldedusing a molding compound (Sumikon EME-7026, manufactured by SumitomoBakelite Company Limited). The package was subject to a moistureabsorption treatment for 196 hours in an atmosphere of 30° C. and 60%relative humidity, and then to an IR reflow treatment (260° C., 10seconds, three times of reflow). The degree of delamination after thetreatments was measured by means of the scanning acoustic microscopedetector (through scan mode). A measured result having a delaminatedarea of a die attach portion of less than 10% was evaluated to havepassed the criteria. A unit of delaminated area is “%”.

Package: QFP (14×20×2.0 mm)

Lead frame: silver spot plated copper frame

Chip size: 9×9 mm

Curing condition of a resin composition: in an oven at 150° C. for 30minutes

Finally, experimental examples of the sixth composition system(Experimental example series F) are hereinafter described. Thecompounding ratio is in “part by weight”.

Examples F1 to F4, Comparative Examples F1 to F3

Polypropylene glycol dimethacrylate (BLEMMER PDP-400, manufactured byNOF Corporation, hereafter referred as “compound 1”), polytetramethyleneglycol dimethacrylate (BLEMMER PDT-800, manufactured by NOF Corporation,hereafter referred as “compound 2”) and as the compound (B),polyether-based bismaleimide acetic ester (LUMICURE MIA-200,manufactured by DAINIPPON INK & CHEMICALS, INC., a compound wherein R²is —C₂H₂— and R³ is —CH₂— in the formula (2), and X¹ is —O— and R¹ is—C₄H₈— in the formula (1), hereafter referred as “compound 3”) wereused.

As the compound (H), a compound (viscous liquid at room temperature,hereafter referred as “compound 4”) wherein after a maleatedpolybutadiene (number average molecular weight: about 1,000, M-1000-80,manufacture by Nippon Petrochemicals Co., Ltd.) andpoly(propyleneglycol-tetramethyleneglycol) monomethacrylate (BLEMMER50PPT-800, manufactured by NOF Corporation) were reacted in the presenceof trimethylamine in toluene at 30° C. for 4 hours, removing a solventunder reduced pressure at 50° C. was performed was used.

As the reactive diluent (I), lauryl acrylate (Light Ester LA,manufactured by KYOEISHA CHEMICAL Co., LTD., hereafter referred as“reactive diluent”) was used. As the thermal radical initiator (C),dicumyl peroxide (decomposition temperature: 126° C. in rapid heatingtest, Percumyl D, manufactured by NOF Corporation, hereafter referred as“initiator”) was used. As the filler (A), silver powder in a flake-likeform having an average particle size of 3 μm and a maximum particle sizeof 20 μm (hereafter referred as “silver powder”) was used. Also, asilane coupling agent having a methacryl group (KBM-503, manufactured byShin-Etsu Chemical Co., Ltd., hereafter referred as “methacryl silane”)was used.

These compounds were compounded in combination as shown in Table 6 andkneaded by means of the three-roll mill followed by defoaming, thusobtained resin compositions.

In Comparative example F1, polyethylene glycol dimethacrylate (BLEMMERPDE-400, manufactured by NOF Corporation, hereafter referred as“compound 5”) was used. In Comparative example F2, acryl-modifiedpolybutadiene (a compound obtained by half esterifying maleatedpolybutadiene with ethylene glycol methacrylate) (number averagemolecular weight: about 1,000, MM-1000-80, manufactured by NipponPetrochemicals Co., Ltd., hereafter referred as “compound 6”) was used.In Comparative example F3, diglycidyl bisphenol A obtained by reactingbisphenol A with epichlorohydrin (epoxy equivalent 180, liquid at roomtemperature, hereafter referred as “bis-A-epoxy”), cresyl glycidyl ether(epoxy equivalent: 185, hereafter referred as “CGE”), phenol novolacresin (hydroxyl group: 104, softening point: 85° C., hereafter referredas “PN”), 2-phenyl-4,5-dihydroxymethylimidazole (product name: Curezol,manufacture by Shikoku Chemicals Corporation, hereafter referred as“2PHZ”) and a silane coupling agent having a glycidyl group (KBM-403E,manufactured by Shin-Etsu Chemical Co., Ltd., hereafter referred as“epoxy silane”) were used.

The obtained resin compositions were evaluated by the following manner.The evaluated results are shown in Table 6.

TABLE 6 Example Comparative example F1 F2 F3 F4 F1 F2 F3 Compound 1 7.83.9 7.8 7.8 Compound 2 7.8 Compound 3 3.9 3.9 3.9 3.9 Compound 4 3.9 3.95.8 5.8  3.9 Compound 5 11.7 Compound 6 3.9 Reactive diluent 3.9 3.9 5.85.8  3.9 3.9 Initiator 0.4 0.4 0.4 0.4  0.4 0.4 Silver powder 80.0 80.080.0 80.0 80.0 80.0 75.0 Bis-A-epoxy 16.1 CGE  6.9 PN  1.1 2PHZ  0.7Methacryl silane 0.2 0.2 0.2 0.2  0.2 0.2 Epoxy silane  0.2 ViscosityInitial value (Pa · s) 18.2 17.6 20.4 22.6 16.4 15.8 21.4 After 48 hours(Pa · s) 18.6 17.4 20.2 22.0 16.6 16.0 21.2 Viscosity increasing rate 2%−1% −1% −3% 1% 1% −1% Adhesion strength 30 seconds curing After curing84 84 90 64 78   63 23   (N/chip) (hot plate) After PCT 74 80 78 56 32  48 8  60 minutes curing After curing 76 76 82 60 64   24 54   (oven)After PCT 64 68 70 54 28   12 24   Soder crack resistance Delaminatedarea (%) <10 <10 <10 <10 50<  <10 50<  Comprehensive evaluation ∘ ∘ ∘ ∘x x x

Evaluation Method of Experimental Example Series F

(1) Viscosity

Using an E type viscometer (3° cone), values were measured at 2.5 rpm at25° C. just after producing a resin composition and after leaving for 48hours at 25° C. A measured result having viscosity of 15 to 25 Pa·s justafter production and viscosity increasing rate after 48 hours of lessthan 20% was evaluated to have passed the criteria. A unit of viscosityis “Pa·s” and a unit of viscosity increasing rate is “%”.

(2) Adhesion Strength

A 6×6 mm silicon chip was mounted on a silver spot plated copper frameusing the obtained resin composition and cured on a hot plate of 200° C.for 30 seconds and in an oven of 150° C. for 60 minutes respectively.After curing and PCT process (121° C., 100%, 72 hours), hot die shearstrength at 260° C. was measured by means of the automatic adhesionstrength tester. A measured result having hot die shear strength at 260°C. of 50 N/chip or more was evaluated to have passed the criteria. Aunit of adhesion strength is “N/chip”.

(3) Solder Crack Resistance

The following lead frame and the following silicon chip were bonded bycuring under the following curing condition with the use of the obtainedresin composition as shown in Table 6 followed by molding by a moldingcompound (Sumikon EME-7026, manufactured by Sumitomo Bakelite CompanyLimited). The package was subject to a moisture absorption treatment for192 hours in an atmosphere of 60° C. and 60% relative humidity, and thento an IR reflow treatment (260° C., 10 seconds, three times of reflow).Then, the degree of delamination of packages after the treatments wasmeasured by means of the scanning acoustic microscope detector (throughscan mode). A measured result having a delaminated area of a die attachportion of less than 10% was evaluated to have passed the criteria. Aunit of delaminated area is “%”.

Package: QFP (14×20×2.0 mm)

Lead frame: silver spot plated copper frame

Chip size: 6×6 mm

Curing condition of a resin composition: a hot plate at 200° C. for 60seconds

INDUSTRIAL APPLICABILITY

A resin composition of the present invention, particularly a resincomposition which belongs to any of the above-mentioned first to sixthcomposition systems, is excellent in adhesion strength, quickcurability, moisture resistance and low stress property, and isexcellent in adhesion particularly between a copper lead frame and asemiconductor chip, therefore, it can be suitably used as a die attachpaste material for a semiconductor chip.

Also, among the resin compositions of the present invention, thecomposition which belongs to the third composition system exhibitsexcellent bleeding property as well as good low stress property and goodadhesion, therefore, the resin composition can be suitably used for asemiconductor chip or a heat dissipating member such as a heat sinkwhich requires the above-mentioned bleeding property, low stressproperty and adhesion at the same time.

The invention claimed is:
 1. A resin composition for an adhesive bondingof a semiconductor chip or a heat dissipating member comprising a filler(A) in an amount of 70 to 95 wt %, compound (B) having formula (1),thermal radical initiator (C), reactive diluent (I) and acrylamidecompound (F) and not containing a photo polymerization initiator;wherein, Filler (A): a filler selected from the group consisting ofsilver gold, copper, nickel, palladium, aluminum nitride, boron nitride,calcium carbonate, silica, alumina and mixtures thereof: Compound (B): abismaleimide compound (B′) represented by the following formula (3):

wherein X² is —O—; each R⁴ is hydrogen atom or methyl group; each R⁵ isa hydrocarbon group having 1 to 11 carbons and containing no aromaticgroup; each R⁶ is a hydrocarbon group having 3 to 6 carbons andcontaining no aromatic group; and “n” is an integer of 1 or more and 50or less; and if the formula contains two or more parts which are denotedby the same symbol, each may be the same or different from each other;Acrylamide compound (F): a compound containing a structure representedby the following formula (6) in a main chain and having at least onefunctional group represented by the following formula (7):

Formula (7)CH₂═CR¹¹—CONH—  (7) wherein X⁴ is —O—, —COO— or —OCOO—; R¹⁰ is ahydrocarbon group having 3 to 6 carbons; R¹¹ hydrogen atom or a methylgroup; “r” is an integer of 9 or more and 50 or less; and if the formulacontains two or more parts which are denoted by the same symbol, each ofthem may be the same or different from each other.
 2. A resincomposition according to claim 1, wherein R⁵ of the bismaleimidecompound (B′) represented by the formula (3) has 1 to 5 carbons.
 3. Aresin composition according to claim 1, wherein R⁵ of the bismaleimidecompound (B′) represented by the formula (3) is —CH₂— or —C₅H₁₀—.
 4. Aresin composition according to claim 1, wherein R⁶ of the bismaleimidecompound (B′) represented by the formula (3) is at least one selectedfrom the group consisting of —C₃H₆— and —C₄H₈—.
 5. A resin compositionaccording to claim 1, wherein the reactive diluent (I) is a vinylcompound which is in liquid form at room temperature other thanacrylamide compound (F).
 6. A resin composition according to claim 5,wherein the vinyl compound is a compound containing at least one(meth)acryloyl group.
 7. A resin composition according to claim 1,wherein R¹⁰ of the structure represented by the formula (6) of theacrylamide compound (F) is at least one selected from the groupconsisting of —C₃H₆— and —C₄H₈—.
 8. A resin composition according toclaim 1, wherein X⁴ of the structure represented by the formula (6) ofthe acrylamide compound (F) is —O—.
 9. A resin composition according toclaim 1, further containing a silane-based coupling agent (J).
 10. Aresin composition according to claim 9, wherein the coupling agent (J)is a silane coupling agent having an S—S bond.
 11. A resin compositionaccording to claim 9, wherein the coupling agent (J) further contains asilane coupling agent having a glycidyl group.
 12. A resin compositionaccording to claim 1, containing a compound (K) having a glycidyl groupother than the silane coupling agent having a glycidyl group.
 13. Aresin composition according to claim 1, further containing the followingcompound (L) and the following compound (M): Compound (L): a compoundcontaining the following structure represented by the formula (11) in amain chain and having at least one glycidyl group:

wherein X⁷ is —O—, —COO— or —OCOO—; R¹⁵ is a hydrocarbon group having 3to 6 carbons; “u” is an integer of 2 or more and 50 or less; and if theformula contains two or more parts which are denoted by the same symbol,each of them may be the same or different from each other; Compound (M):a compound having a functional group which can react with the glycidylgroup of the compound (L).
 14. A resin composition according to claim13, wherein the repeating unit (X⁷—R¹⁵) of the compound (L) is the sameas the repeating unit (X¹—R¹) of the compound (B).
 15. A semiconductordevice comprising the resin composition defined by claim 1 as a dieattach material.
 16. A semiconductor device comprising the resincomposition defined by claim 1 as a material for bonding a heatdissipating member.
 17. A resin composition according to claim 1,wherein the acrylamide compound (F) is a compound obtained by reacting acompound having a hydroxyl group on each end, at least one repeatingunit selected from a group consisting of propylene oxide, tetramethyleneoxide and butylene oxide, and a molecular weight of 300 to 2,500, withdibasic acid anhydride and then with (meth)acrylamide having a hydroxylgroup.
 18. A resin composition according to claim 17, wherein thedibasic anhydride is succinic anhydride, and the (meth)acrylamide havinga hydroxyl group is 2-hydroxyethyl(meth)acrylamide.